Fuse-plug



A. F. DAUM.

FUSE PLUG,

APPLICATION FILED SEPT. I2, 1914 Patented Aug. 31, 1920.

JHbQrT f Wane bozo v gagw UNITED STATES ALBERT F. DAUM, 0F PITTSBURGH, PENNSYLVANIA.

FUSE-PLUG.

Specification of Letters Patent. Patented Aug. 31, 1920.

Application filed September 12, 1914. Serial No. 861,414.

To all whom it may concern:

Be it known that I, ALBERT F. DAUM, a citizen of the United States, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Fuse Plugs, of which the following is a specification.

My invention relates to improvements in fuse plugs, and has particular relation to devices of this type which are refillable at the will of the user.

Among the objects of my invention are to provide a fuse plug which can be readily refilled; which requires no tools in securing the fuse in position or removing a blown fuse; which will provide for eificient contact; in which the fusible element will be retained attached to the plug when removed; in which a fuse strip may be employed; and which can be manufactured and maintained in service at a minimum cost.

To these and other ends, the nature of which will be readily understood as the invention is hereinafter disclosed, my invention consists in the improved construction and combination of parts hereinafter fully described, illustrated in the accompanying drawings, and more particularly pointed out in the appended claims.

In the drawings, in which similar reference characters indicate similar parts in each of the views,-

Figure l is avertical sectional view of a fuse plug according to one form of my invention.

Fig. 2 is a top plan view of the same with the cap removed.

Fig. 3 is a detail view of a fuse strip which may be employed. 4

Fig. 4 is a view taken at rightan'gles to F ig. 1, showing a slight modification.

Fig. 5 is a top plan view of the same with the cap removed.

Fig. 6 is a detail sectional view showing a modified form of positioning the outer end of the fuse on the shell.

Fig. 7 is a detail sectional view showing the fuse in the form of'a wire.

Owing tothe necessity of replacing the plugs as an entirety when the fuse element blows, the cost of maintaining service through the use of plugs has been an expensive matter, especially where the installation is such as to provide for carrying heavy loads. To overcome these objections attempts have been made to apply the refillable idea to this type of protective devices, thus reducing maintain-since expense to the cost of the fusible elements, the casing and cap being retained for further service. These devices, however, so far as 'I am aware, have generally had features which in one way or another acted to prevent commercial adoption generally. Among these features are the fact that the arrangements are such as to require the use of tools in positioning or removingthe fusible element, with liability of short-circ'uiting the leads by the tool, the liability of receiving a shock, and the necessity for care in manipulating the parts; the use of a number of movable parts which are liable to become lost, or which, when being manipulated, are liable to become damaged; and, finally, the ex cessive cost of manufacture, due to the requirement for drilling holes, threading them, the use of threaded members to enter the holes, the accurate positioning of parts, etc., all of which combine to increase the initial cost as well as necessitate the expenditure of considerable time in removing the blown fuse and refilling the plugs. These disadvantages are overcome in the present invention by the following construction and ar rangement of parts.

In the drawings, 10 designates a plug casing of suitable insulating material, such as porcelain, said casing being hollow as shown, and provided with the usual threaded ferrule 11 forming one of the terminals of the fuse plug, cooperating with the socket as is usual with this type of structures. The casing is provided with an external longitudinal slot or recess 12 in which is located the angular conductor 13 having one end secured to the ferrule 11., the opposite end, indicated at 12, extending laterally through the casing at or adjacent the open end of the easing into the casing interior, said end 12* being preferably provide l with a recess 12, positioned at the free end or at the side, as may be desired, this recess being adapted to receive the fuse, indicated at 13, either in. the form of a strip or of wire, as desired.

The closed end of the casing is provided with a teat or projection 14, preferably inte gral with the casing, and extending through the closed end, adjacent the teat, is a slot or opening 15 through which the fuse is adapted to extend. If desired, theclosed end may have an additional depression of suitable type, indicated at 16 in Fig. 6, into which the outer end of the fuse may extend,

said depression being of any desired form, that shown in Fig. 6 being simply an example.

The open end of the casing is closed opening 17, 1nd the usual dish 18 0 or other insu sting material.

end 12 1s so located elutively to the dislc 1.8, as to cause the lotr es the cup is three l-cl to position, to up- 4 in or end sul'hciently close to clzunp the fi 13 between the dish and arm,

portmn of the cup hein ufficient to prevent the dish oeing dzimzu As the dish isof u size to prooutwsrdly beyond the fuse, 1t

puss into contact with the metallic portion of the cup. iii-Jud since the arm 19.; is

to provide good conductor, the extended co'zituct of fuse and arm will provide suffiudjucent the cup. l

i i preferred form of fuslble element is lhis may be of the usual form, having parallel sides throughout its length, but I lsrgement adapted to form a shoulder 13*, said shoulder forming an abutment to pre slot or opening lo this feature being 0 vantage in preventing the exposed i'lsuul cup 17, preferably provided shown, arm or the si ort afforded the (llSlZ by the annular m during the trump notion.

understood that thellutter is not extended urea and of proper cross-section cient metallic contact to prevent blowing shown in Fig. 3 in the form of strip 13.

prefer to form the strip with a lutenl envent a free pusss e of the fuse through the the fuse dropping out during removel of the plug after the fuse has blown, the shoul der being loceted on the inner side of the closed end and consequently retaining the free end of the blown fuse in position while the plug); is hell g withdrawn, thus inn any necessity of fishing for the free end, or of short-circuiting the leads free endror the tool used in the h operation. in alternative routes for pro this result with the strip is to place :1 kink in the strip to event its pucccgl e through the slot. li here A e ruse is inrthe form of u wire strand or tru ds, es in Fig. 7, this kinking strucis preferred. 7 l y scoring the strip, st 13 fusible materiel nos be used to su m. y rusiblo elementsiof various capacity, hein necessary to split theelemcnt along or the lines to decrease the capacity to the desired extent. 7

is shown in the druwings,tl1e fuse has one end passed through the slot 15 and bi: right across the face of the Cost or projection 14, this forming the opposite terminal of the iilugi the other end of the fuse being; carried over the outer face of the arm. or end 1%,

with it, the fuse removed and rcpluci being seztted in the recess 12"., and clamped to positlon by the threu dlng of the cup to POSltlOlL liy this arrangement it will be readily understood that the cost oi; manufacture is small, the ferrule and cup being of usual con.-

str ction, while coiiduc fa form r4 (lily stamped out; the plug; 1s of e form winch. can be reshl molded; the assemhlinu' of ports is W requiring only e secui' of the conductor to the ferrule. (lf these parts the only removable portionsn're the up and n'iicedislr end these re 0 :1 size and shape not readily lost and uluted as to he prscticznly free from dumis will he reucily uiu'lerstood, the E103:

therein may be required or desired to meet the exigencies of use, and I desire to bounderstood as reserving the right to make any .70 so inzuupand all such changes and modifications as may be so required, inso fsrastheseine may fall within the spirit and scopeof the i invention as expressed in the accompanying clan is. V

Having thus described my invention, what I claim'as new is:

1. In a fuse plug having'a cap, a terminal conductor carried by the plug and extendingwithin the plug body with its inner end approaching the axis of the plug, said terminal cooperating with the cap in clamping the fusible element in position;

2. In a, fuse plug, a hollow casing having a fixed terminal leading to the interior of the casing, ands removable cap for the open end of the casing: said terminal having its inner end approaching the axis of the plug within the interior of the casing to cooperate with the cap in clamping the fusible element in position. 3. A refillable fuse plug comprising a hollow casing having a closedend. perforated for the passage of thefusible element and having an externalnon-metallic seat for the element, the element passageway being out of alinernent with said seat, Et'fiXGCl terminal carried by the casing and projecting into the casing at its open end, ands, removable cap and insulating disk for such open end, said cap and dislr'cooperating with the terminal to clump the fusible element in position."

4. In a fuse plug, a hollow casing having a fixed terminal projecting into the casing at its open end, and a removable cap and disk for closing said end, said terminal having a recess to receive the fusible element and prevent its shifting, and being positioned to cooperate with the cap and disk in clamping the fusible element in position.

5; In a plug fuse and in combination, a hollow caslng having a fixed terminal, said casing having a closed end provided with an external seat and being perforated adjacent the seat, a removable cap and disk to close the open end of the casing, and a fusible element having an off-set intermediate its ends, said element having one end clamped by said terminal and the cap and disk, and

having its opposite end leading through the perforation of the casing end and seated on said seat, said ofi-set forming an abutment internal of the casing to retain the free end of the element upon blowing of the element.

6. A fusible element for fuse plugs having an off-set intermediate its ends and extendin in the facial plane of the element, said 0 -set being positioned to form a supporting abutment for the element within the element-disrupting chamber ofthe plug.

7. In a fuse plug, a hollow casing having a permanently closed end provided with an external seat for a conducting element, said closed end being perforated for the passage of the element and having a recess adapted to receive the free end of the element, said passage and said recess being spaced apart by said seat.

' 8. A renewable fuse plug including a chambered body-member having an aperture in its wall, in combination with a separable fuse-strip having an intermediate portion disposed within the chamber of the bodymember and an end-portion disposed in said aperture, and means on the strip for normally holding the strip from endwise movement through said opening, said means being also disposed within the chamber of the body-member and engaging with the inner face of the wall thereof.

In testimony whereof, I aflix my signature in the presence of two witnesses. L

ALBERT F. DAUM. Witnesses:

L. H. MCCABE, S. H. ALLEN. 

